Re: extern storage class & multiple declaration

[Jan-Benedict Glaw <jbglaw@lug-owl.de>]

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On Thu, 2002-08-22 07:52:34 -0000, Alina Valea <avalea@home.ro>
wrote in message <20020822075234.20104.qmail@relay1.home.ro>:
> Hello everybody,
> 
> Suppose we have:

[
	file.h declares a variable,
	file.c defines it, but doesn't use it and
	some_file.c includes file.h and uses mentioned variable
]

> I know this is entirely correct, but is it an acceptable
> programming habit?

This is not only correct but also done very often. Sometimes, you can't
go around global variables. In such a case, it's better to have a
"globals.h" (declaring *all* global variables) and a matchins globals.c
file (defining them all, possibly initializing them to useful default
values).

This is a _lot_ better than spreading all those global variables over a
zillion .c files, and locally declaring them in any .c file which uses
(but doesn't define) it. That's quite error-prone (eg. small things like
signed <-> unsigned conflicts *will* come up at some time, and you'll
spend a day or two for searching the difference).

Having all global variables (if any exist) iat one place (in conjunction
with a matching header file) is a good thing helping to not do stupid
mistakes...

MfG, JBG

-- 
Jan-Benedict Glaw   .   jbglaw@lug-owl.de   .   +49-172-7608481
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